The studies proposed will investigate the pathways involved in the pathogenesis of animal glaucoma so that rational modes of therapy can be evaluated and subsequently applied to human glaucoma. Experimental models for glaucoma should demonstrate the following characteristics: (1) reproducibility of the clinical course of the disease, (2) evidence of selected recognizable characteristics of human glaucoma, e.g., elevated intraocular pressure, diminished aqueous humor outflow or augmented aqueous humor inflow, and cupping of the optic disc, (3) demonstrable response to therapeutic approaches known to be effective in human glaucoma, and (4) adaptability to newer modes of glaucoma therapy. This investigation would use a prostaglandin induced elevation of intraocular pressure in the Rhesus monkey to evaluate "secondary glaucoma", the hereditary buphthalmic rabbit for the investigation of hereditary human glaucoma and finally the Cebus monkey as a model for "ocular hypertension".